Curvature correction method based on subthreshold currents for bandgap voltage references

This work presents a curvature correction method using a subthreshold current generated by an NMOS transistor with its gate and source connected. The designed BGR, used as case study, achieves a simulated temperature coefficient of 5.9 ppm/°C, while the conventional circuit achieves only 17.5 ppm/°C - the triple of the output voltage variation in the temperature range from -40 to 125°C. If the proposed technique is used, the traditional first-order BGR can be simply modified to accomplish high-order temperature compensation with small area overhead and without an increase in power consumption.